Relationship between Size of Myocardial Infarctions Assessed by Delayed Contrast‐Enhanced MRI after Primary PCI, Biochemical Markers, and Time to Intervention

Background The quantitative assessment of myocardial infarctions using delayed contrast‐enhanced magnetic resonance imaging (MRI) has recently been validated using postmortem histopathological animal studies. In a prospective study, we investigated the correlation between infarct size as assessed by delayed contrast‐enhanced MRI, elevation of creatine kinase (CK), and c‐reactive protein (CRP) as well as the time from onset of symptoms to intervention. Methods Four to 10 days after immediate PCI in 45 acute ST‐segment elevation myocardial infarction (STEMI) patients (<24 hour) with stenting of the infarct‐related artery and treatment with abciximab, we performed gadolinium contrast‐enhanced three‐dimensional inversion recovery gradient‐echo MR sequences with complete coverage of the LV‐myocardium in short‐axis slices. The mass of infarcted tissue based on the volume of hyperenhanced myocardium was calculated and linear regression analysis was performed to assess the correlation between absolute size of infarctions (g) as well as relative size (LV%) with peak values of CK, CRP, and the time to PCI. Results There was a significant correlation between absolute size of infarctions (g) and peak CK values (r = 0.72; P < 0.001) as well as the relative size (LV%) and peak CK (r = 0.77; P < 0.001). No correlations were found between absolute size (r = 0.33) as well as relative size (r = 0.27) of infarctions and peak CRP. There was also no correlation between absolute (r = 0.29) as well as relative size of infarctions (r = 0.27) and the time from onset of symptoms to PCI. Conclusions In patients with acute STEMI (<24 hour) undergoing immediate PCI with stenting and treatment with abciximab, peak CK values correlated well with infarct size as assessed by delayed contrast‐enhanced MRI. There were no correlations between infarct size and peak CRP as well as the time to intervention.